US2161836A - Box stacker - Google Patents

Description

June 13, 1939. J. w. STEVENSON 2,161,836

BOX STACKER 3 Sheets-Sheet 1 Filed Jan. 11, 1937 June 13, 1939. J. w. sTEv ENs oN BOX STACKER Filed Jan. 11, 1937 3 Sheets-Sheet 2 J. w. STEVENSON June 13, 1939.

BOX STACKER 3 Sheets-Sheet 5 Filed Jan. 11, 1937 Patented June 13, 1939 1 uurrso- STATES PATENT OFFICE ment of this designed for use in citrus packing houses is disclosed herein.

Citrus fruits are harvester by being picked-from the trees by hand and are brought to the packing house from the groves in what are known as field boxes. At the packing house these loaded boxes are taken from the truck and stacked on the floor in stacks of anywhere from five to eight boxes high. When it is desired to remove the fruit from these boxes and run it through the series of treatments by which it is prepared for market, the fruit of course must be dumped from the boxes containing it and the empty boxes delivered to empty box storage. Clamp trucks are provided by which an entire stack of boxes can be very easily handled and moved from place to place on the packing house floor by a single worker.

It is an object of my invention to provide a machine to which loaded boxes may be delivered in the form of stacks and which will dump the contents from the boxes in these stacks and form the empty boxes into stacks for storage. 1

In stack dumpers previously in use, there has always been a pause between the dumping of the last box in a given stack and the first box in the next stack which is longer than the interval between the dumping of successive boxes in each stack. This resulted in irregular feeding of fruit to the various machines for treating this, with corresponding decrease in emciency in these machines.

It is therefore another object of my invention to provide a stack handling device which will deliver individual boxes of a series of stacks successively to a box dumper or other mechanism so that the interval between the delivery of the last box of each stack and the first box in the next succeeding stack is the same as the intervals between the delivery of successive boxes in a given stack.

The stacking of boxes in the citrus industry is not only necessary after the contents have been dumped from the box, but also when the boxes are first received from the groves into the packing house. It is, therefore, another object of my invention to provide a novel and efficient box stacker which may be used either for handling loaded or empty boxes.

The manner of accomplishing the foregoing objects, as well as further objects and advantages, will be made manifest in the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a diagrammatic cross sectonal view of a preferred embodiment of my invention.

Fig. 2 is a. cross sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a plan view of the upper portion of Fig. 1 showing the drive mechanism.

Fig. 4 is a side elevational view of Fig. 3 taken in the direction of the arrow 4 and illustrating that portion of the drive mechanism on that side of the machine.

Fig. 5 is a diagrammatic fragmentary detail view of a rest disposed as when supporting a box in-dumping position.

Fig. 6 is a cross sectional view taken on the line 63 of Fig. 3.

Fig. '7 is an enlarged fragmentary cross sectional view illustrating additional steps to those shown in Fig. 1 of the dumping of a box and just after a new stack has been received into the machine.

Fig. 8'is an enlarged fragmentary cross sectional view of a portion of the apparatus shown in Fig. 1 and illustrating the ejection of a stack just formed and the starting of a new stack;

Fig. 9 is a fragmentary perspective view illustrating a stack forming cradle of the stacker of my invention and the manner in which this oper- The stack feed conveyer 12 The stack feed conveyer I2 is mounted in a floor 20 upon which the frame ll rests and comprises a pair of chains 2| which pass around idle sprockets 22 and drive sprockets 23, the latter being fixed on stub shafts 24 with driven sprockets 25. Provided on the chains 2| are stack spacing lugs 26.

The stack elevator 13 The stack elevator l3 includes an endless chain mechanism 30 having a drive shaft 3|, stub shafts 32, and sprockets 33 and 34 fixed on these shafts about which sprockets are trained endless chains 35. Fixed on the shafts 32 and disposed outwardly from the sprockets 34 are drive sprockets (not shown) which are connected by endless chains 33 with the driven sprockets 25 so that whenever the sprockets 34 are rotated by the chains 35, the sprockets 25 are also rotated thus setting in motion the box stack feed conveyer I2.

The chain mechanism 30 is mounted so as to be inclined away from the stack conveyor I2.

The space Just in advance of endless chain mechanism 30 may be termed a stack elevating path 39. Bordering this path and located between the endless chains 36 Just back of the path 39 is an inclined back plate 31 which is supported on the frame II by members 99. Also mounted on the frame I I and extending substantially parallel with the foremost flights of the chains 35 are guides 4|. Back of the chains 35 are provided guides which are secured upon the frame II.

The stack elevator I3 also includes two stack lifting cradles 41 each of which comprises a pair of right triangular frames 49 which are connected at their right angular vertices by a cross bar 49. The lower, vertices of the triangular frames 49 are connected by a cross bar the extending ends of which are pivotally connected to thechains 35 so that each of the cradles 41 is supported on these chains. Extending ends of the bar 49 form guide pins 5| which slide against inner faces of guides H as shown in Fig. 2.

When the chains 35 are caused to traverse their endless pathway by the rotation of shaft 3|, each of the cradles 41 is caused to travel upwardly when it is disposed in the path 39, the cross bars 49 and 50 being guided at this time between the. back plate 31' and the inner edge portions of the guides 4|. During this upward travel of a particular cradle 41,, the center of gravity of that cradle, as well as any weight which might be imposed on it, maintains the pins 5| of such cradle pressed against the inner edge portions of the guides 4 I. Thus, as this cradle is propelled upwardly above the sprocket 3|, it remains in the same rising position in which the rising cradle is shown in Fig. 1 until the pins II thereof engage traps which start rocking this cradle rearwardly. The frames 49 of this cradle then engage the shaft 3I causing the cradle to flop backward until the pins 5| engage guides 45 as shown in Fig. 7.

Approaching the lower end of the chains 35, the downwardly moving cradle 41 is swung forwardly by engagement of'the cradle frames 49 with a fixed bar 49. The center of gravity of the descending cradle 41 thus shifts forward of the cross bar 50 of this cradle with the result that the cradle swings over until the pins 5| thereof I engage the lower ends of the guides H. A comare dumping bars 92 and 93.

plete cycle of travel of one of the cradles 41 has now been described.

The dumping mechanism 14 The dumping mechainsm I4 includes a fruit receiving hopper 96 above which is supported a 'pair of rollers 66 and a roller 91 having arms 99 which are normally inclined downwardly. The roller 61 has a short arm 69 extending in the opposite direction from the arms 69, the arm 69 having a pin 10 which is trapped in an elongated eye II of a link 12, the lower end of which is pivoted on a short arm 13 fixed on a free end of the shaft H (see Figs. 1 and 5). Journaled on the frame II (see Figs. 1, 3 and 4) is a shaft 19 having a drive sprocket I1 and driven sprockets 19, the latter being connected by short endless chains I9 to small sprockets 90 mounted on stub shafts 9|. Carried between the two chains 19 A fulcrum bar 95 is fixed on the frame Just outwardly from and on the same level as theroller 61.

The empty boa: convever 15 The empty box conveyer I 6 includes shafts 99 and 91 which are Journaled on the frame II and provided with sprockets 99 and 99. Mounted on suitable stub shafts so as to be in alignment with the sprockets 99 and 99 are small sprockets 90 and 9I, endless chains 92 encircling the sprockets thus in alignment. Carried by the chains 92 are a plurality of empty box conveying bars-93. Provided on the frame II are guide rails 99 for supporting the lower flights of the chains 92 and box rails 91 for supporting a box while it is being conveyed by one of the bars 93. For driving purposes the shafts 99 and 9'! are connected by sprockets 99 and 99 rigidly fixed on these shafts and an endless chain I00 encircling these sprockets. It might also be pointed, out here that the sprockets 99 are loosely mounted on the shaft 96 and the sprockets 99 are fixed upon the shaft 91.

Fixed on the rear end of shaft 96 is a spur gear I06 and a sprocket I06, the latter being connected with the sprocket II by a chain I0l.' Journaled in suitable bearings provided on the frame II is a shaft I09 having a spur gear I09 at one end which meshes with the spur gear I05 and at the opposite end a sprocket I I0 and a drive pulley I II. The sprocket II 0 is connected by an endless chain II2 to a sprocket II3 mounted on the front endof the shaft 3I. The entire machine I0 is adapted to be driven by any suitable prime mover (not 'shown) by rotating the pulley III as by a belt II4.

Also fixed on the shaft 91 is a sprocket II9 which is connected by an endless chain II9 to a sprocket I20, the latter being fixed upon another shaft I2I also journaled on the frame II. The shaft I2I has fixed thereon sprockets I22 which are connected by endless chains I23 to sprockets I24 provided on stub shafts I25 mounted on the frame II. Attached to and carried between the chains I23 is a box-leveler cross bar I26. Pivotally mounted at I2I on the frame II is a stack latch I29 having a serrated foot I29 at its lower end.

The stacker 16 and empty stack cohveyer 17 United with the sprockets I33 on the stub shafts I3I are other sprockets (not shown) which are connected by endless chains I31 provided on a shaft I39 of the empty stack conveyer II. Shaft I39 has sprockets I39 which are connected by endless chains I 40 to sprockets III, the latter being mounted on a shaft I42, and thence about other sprockets to carry the chains I40 about an endless path.

Secured on the end of the shaft 91 is a drive pinion I44 and in alignment with this is a sprocket I45 which is idly carried on a stub shaft I49 mounted on a bracket I4'I directly over the shaft 91. The sprockets I44 and I45 are connected by an endless chain I 49 to a sprocket I49 Provided on the frame II at the right-hand or I39 to drive sprockets fixed upon the front end of the shaft I30 (see front of the box stacker I9 are cradle guides I55.

At the top of the stacker I6 is a pair of guides I5I and I59, the latter extending downwardly to the bottom of the stacker. The upper ends of the guides I59 which, as shown in Figs. 1 and 8, are secured to the upper, ends of the guides I 55.

have upwardly bent portions I59 -Pivotally'mounted on a shaft I80 is a stack ejector I5I which comprises a pair of vertical members I82, 9. cross member I83 connecting the upper ends of these, and a pair of elephant ears I54 as shown inFig. 8. Provided on'the shaft I50 is a weight I55 which tends at all times to return the ejector I5 I to its reclining position in which its upper end rests in a recess provided ina frame member I85, as shown in Figs. 1 and 8.

Also provided on shaft I80 are leaf springs I51.

(see Fig. 1). I

Carried between the chains I34 isa pair of stack forming cradles I10, each of these cradles comprising a pair of triangular frames I1I connected by a bar I12 at the lower vertices of the triangular frames IN. This bar has laterally extending ends I13 which pivottally connect with the chains I34 as shown in Fig. 8'. Also provided on the triangular frames "I are pins I14 and I15. The manner in which the cradles I10 operate when the chains I34 travel about their endless path due to rotation of the sprockets I32 and I33 is as follows. When either of the cradles I10 is travelling downwardly with the forward flights of the chains I34, the guide pins I14 engage the guides I55 until the frames I1I thereof engage the shaft I50 which swings this cradle rearwardly. The leaf springs I51 are in alignment with the pins I14 and are now engaged by the latter to rock the cradle over with pins I14 in engagement with the guides I58. When either of the cradles approaches the uppermost end of the chains I34 the guide pins I14 of this cra le pass into the forwardly bent portions of the guides I51 and I58 and thus swing this cradle forwardly bringing the pins I15 thereof against the elephant ears I54 of the box stack ejector I5I as shown in broken lines in Fig. 8 and in full lines in Fig. 9. This shifts the box stack ejector outwardly into vertical position and causes the pins I14 to run out from between the forward ends of the guides I51 and I58 and travel upwardly along the inner faces of the guides I55. As the' bar I12 of this cradle passes upwardly over the sprockets I32 so as to lift this cradle into its uppermost position, the pins I15 pass upwardly beyond the upper extremity of the elephant ears I54 thereby permitting the weight I55 to swing the stack ejector I5I back into its reclining position as shown in full lines in Figs. 1 and 8.

Operation To set in operation the combined box stack dumper and empty box resta'cker I0, power is applied through the belt II4 to the pulley III so as to rotate the latter in the direction indicated by the arrows in Figs. 3 and 4. This rotates the shaft I08 which through the sprockets H0 and H3 and the chain II2 rotates the shaft 3I which sets in motion both the stack elevator I3 and the stack feeder I2. Also, through the gears I08 and I05, the sprockets I05 and 11, and the chain I01, the box dumping mechanism I4 is set in operation. As already noted, the rotation of the shaft 85 by the gears I05 and I08 transmits power through I44 on the end of shaft 81 (see Fig. 4) drives the box stacker I5 through the chain I48 and the sprocket I48. As above mentioned, empty box stack conveyer I1 is connected to the stacker I5- so that when the stacker is operated this also sets I in motion the empty stack conveyer I1.

When the machine I0 has thus been started, the attendant trucks stacks of boxes S from their place of storage on the floor of the packing house and sets these down on the chains 2| of the feed conveyer I2 between the lugs 28 as shown in Fig. 1. The lugs 25 are so placed on the chains 2| that these stacks S are successively delivered, with the lowermost box in the stack extending into the elevating path 35, just as one of the cradles 41 rises upwardly into position to support this stack, tilts it into position in the path 35 against the back plate 31," and starts elevating it upwardly towards the box dumping mechanism I4. The latter mechanism is so timed that as each of the boxes B in a stack S being thus elevated comes into a certain position relative to the dumping mechanism, which may be termed a dumping position, the bar 82 engages the side of this box and starts to tip it toward the right against angle iron fulcrum bar 85. As the bar 82 completes its tilting action on the side of thisbox, the bar 83 comes into play against the bottom of the box and continues the rocking of the latter with the result that the box is dumped over completely on its side, coming to rest temporarily in the position shown in'broken lines I80 in Fig. 1.

After the box under discussion has remained in the position I80 a sufficient length of time for the fruit to gravitate entirely therefrom into the hopper 55, the arms 58 are lifted by the downward movement of the short arm 13 and the engagement of the upper end of the eye H with the pin 10 as shown in Fig. '1 in full lines. This lifts the box just as one of the cross bars 93 moves into contact with the empty box so that the later is immediately shifted, as indicated by the broken lines I85 in Fig. '7, onto the rollers 55 and empty box rails 91,

As the first of the boxes is thus dumped and the empty box carried away by one of the bars 83, the next box of the stack is being liftedupwardly into dumping position which is indicated by the broken lines I85 in Fig. '7. As the box reaches this position the cross bar 82 moves into contact with the adjacent side of the box so as to initiate the dumping of this box as already described for the first box. In this manner the boxes of the stack S are successively elevated and dumped and the empty boxes propelled by convey- .ing bars 93 of the conveyer I5 along the empty of the lowermost box of the preceding stack as elapses between the dumping of successive boxes in a given stack. Thus the dumping of fruit in the operation of my machine I0 is at a. uniform rate, there being no fluctuation in the interval between the dumping of successive boxes so long the feed conveyer stacks S.

As shown in Fig. 1, each of the empty boxes is propelled by one of the bars 93 into a position where this box is just beyond the right hand end I2 is kept supplied with ofthe empty -box---rails I1 and disposed directly over the box stacker I, after which this bar ll passes around the sprockets II and then upwardly parallel with the bottom of the box. From the time that this box first starts to project over the right-hand ends of the rails ll the'top of the box is engaged by the box leveler bar I" to support this box and prevent its falling to the right as the rails 01 are no longer under the center of ravity of the box. when this box is entirely free from the rails '1, however, it is then free to move downwardly and rock slightly into alignment with the box stacker ll.

Where this is the first box of a stack, one of cradles I" will be found in its uppermost position as shown in full lines in Fig. 8 and this box will be'deposited directly upon this cradle. As

' will be recalled, each cradle I10 when in its uppermost position has just swung the stack ejector i ii into vertical stack ejecting position as shown in Fig. 9, and then has released this to permit it to return to broken line position it! as shown in Figs. 1 and 8. When this cradle, therefore, starts to move downwardly with the descending flights of the chains I, this first box of the stack is carried downwardly on this cradle outside of the stack ejector IN as clearly shown in Fig. 1.

As successive boxes of a stack are dumped and the empties carried toward the right, as shown in Fig. 1, these are successively positioned as the second box is shown in Fig. 1 overthe descending, partly formed stack of empty boxes and dropped on the preceding box and thus added to the stack so that eventually the entire stack of loaded boxes have been emptied and restacked in the formation of a stack of empty boxes. -This occurs just as the other of thecradles I" has returned upwardly to brlngits pins I'll between the guides I51 and I 58 thereby causing pins I15 of this cradle to engage the elephant ears I which shift the stack ejector "I into vertical position and eject this newly formed stack onto the chains 0 of the empty stack discharge conveyer II.

When thus ejected the stack is held against 45 rocking backward by engagement of the serrated foot II! of the stack latch I28 with the upper box as shown in Figs. 1 and 8. v

A complete cycle of operation of the machine Ill of my invention has now been described. This 50 cycle is repeated automatically as long as the feed conveyer I2 is supplied with stacks S of loaded boxes. Whilethe stacker Ii of my invention is here shown as being used to stack empty boxes,

and while these are shown as being stacked on 55 their sides, I do not desire my invention to be restricted to this use of the stacker l6 as this stacker maybe used to stack loaded boxes in upright position if it is so desired.

While I have shown but a singl embodiment of no my invention it is understood tha many changes and modiiicationsmight be made in this and the -invention embodied in many diflerent forms withformed in said path, said ejecting means vertical away from'the direction towards which" said stacks are to be delivered; endless'chain means disposed substantially parallel with and adjacent said path; a plurality oi stack supporting cradles pivotally mounted on said chain means; means for operating said chain means and guiding said cradles to cause each of said cradies inturn to be relatively quickly extended into said path adjacent its upper end, lowered through said path until adjacent the lower end of said path, swung out of said path, and elevated to a position adjacent the upper end of saidpath; means for delivering boxes at regular timed intervals into a position at the upper end of said path from which position said boxes are permitted to move downwardly to form a stack of boxes on each of said cradles as it travels downwardly through said path; and means for ejecting from said path each stack of boxes so formed in time to permit the one of saidcradles disposed upwardly in said path to receive the next box from.

said position as the lowermost box in the next succeeding stack to be formed.

2. A combination as in claim 1 in which said stack ejecting means swings said stacks into vertical position in ejecting them from said path.

3. A combination as in claim 1 in which said stack ejecting means swings said stacks into vertical position in ejecting them from said path; and means forreceiving said stacks from said ejecting means and conveying said stacks in close order away from said stack forming path.

4. A combination as in claim 1 in which said stack ejecting, means is pivotally mounted adjacent the lower end of said path and extends rearwardly of said path while the stack is being being automatically swung into vertical position in delivering each stack from said path.

5. A combination as in claim 1 in which said stack ejecting means is pivotally mounted adjacent the lower end ofsaid path and extends rearwardly of said path while the stack is being formed in said path, said ejecting means being automatically swung into vertical position indelivering each stack from said path; and means for automatically returning said ejecting means to its normal position behind said path immediately following the discharge of a stack of boxes so. as to prevent said ejecting means interfering with the formation of the next stack of boxes.

6. A combination as in claim 1 in which said ejecting means is actuated to eject a stack from said path in repsonse to the movement of one of said cradles into said path.

JAMES'W. STEVENSON.

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